Testing performance time of an application over a virtual network involves measuring an application's total response time. Such response time may be the sum of the time periods during which application traffic spends over the elements it passes through in the network, until a response to a particular command is received. Total response time of an application may not reveal where in a chain or path of network elements a bottleneck exists, and the extent to which one or more of such bottlenecks may contribute to the total response time. This information may help in optimizing application response time, testing the impact of application parameters on application response time, testing the impact of network parameters on application performance time, and more.